Former officer Robert Faulcon, Sgts. Robert Gisevius and Kenneth Bowen, Officer Anthony Villavaso and retired Sgt. Arthur Kaufman were convicted of charges stemming from the cover-up of the shootings.
All but Kaufman were convicted of civil rights violations stemming from the shootings. Kaufman, who investigated the shootings, was charged only in the cover-up.
"This was a critical verdict. I cannot overstate the importance of this verdict. The power, the message it sends to the community, the healing power it has," U.S. Attorney Jim Letten said after the verdict.
The federal jury did not find that the shootings amounted to murder.
Prosecutors said the officers shot unarmed people without justification and without warning, killing two and wounding four others on Sept. 4, 2005, then embarked on a cover-up involving made-up witnesses, falsified reports and a planted gun.
Defense attorneys countered that the officers were returning fire and reasonably believed their lives were in danger as they rushed to respond to another officer's distress call less than a week after Katrina struck.
Kaufman remains free on bond until he is sentenced, while the other four officers remain jailed. Sentencing has been scheduled for Dec. 14.
The Associated Press contributed to this report.